xfs
[Top] [All Lists]

[PATCH v2 07/11] xfs_repair: force not-so-bad bmbt blocks back through t

To: Dave Chinner <david@xxxxxxxxxxxxx>
Subject: [PATCH v2 07/11] xfs_repair: force not-so-bad bmbt blocks back through the verifier
From: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx>
Date: Tue, 25 Aug 2015 22:24:30 -0700
Cc: xfs@xxxxxxxxxxx
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <20150826005447.GS714@dastard>
References: <20150826003220.23973.59731.stgit@xxxxxxxxxxxxxxxx> <20150826003305.23973.65768.stgit@xxxxxxxxxxxxxxxx> <20150826005447.GS714@dastard>
User-agent: Mutt/1.5.21 (2010-09-15)
If during prefetch we encounter a bmbt block that fails the CRC check
due to corruption in the unused part of the block, force the buffer
back through the non-prefetch verifiers later so that the CRC is
updated.  Otherwise, the bad checksum goes unfixed and the kernel will
still flag the bmbt block as invalid.

v2: Halt all readahead on the bmapbt if any of its blocks produce an
error.

Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
 repair/prefetch.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/repair/prefetch.c b/repair/prefetch.c
index 1de3ec0..32ec55e 100644
--- a/repair/prefetch.c
+++ b/repair/prefetch.c
@@ -276,6 +276,18 @@ pf_scan_lbtree(
 
        XFS_BUF_SET_PRIORITY(bp, isadir ? B_DIR_BMAP : B_BMAP);
 
+       /*
+        * If the verifier flagged a problem with the buffer, we can't trust
+        * its contents for the purposes of reading ahead.  Stop prefetching
+        * the tree and mark the buffer unchecked so that the next read of the
+        * buffer will retain the error status and be acted upon appropriately.
+        */
+       if (bp->b_error) {
+               bp->b_flags |= LIBXFS_B_UNCHECKED;
+               libxfs_putbuf(bp);
+               return 0;
+       }
+
        rc = (*func)(XFS_BUF_TO_BLOCK(bp), level - 1, isadir, args);
 
        libxfs_putbuf(bp);

<Prev in Thread] Current Thread [Next in Thread>